Measurement of muscle strength is an essential to check degree of muscle weakness and detects change of muscle strength.
To measure the muscle strength, a weight or a dynamometer has been often used.
There is a problem in that in the case of measuring the muscle strength using the weight, a plurality of instruments with various weights is required. And the dynamometer is expensive and requires a professional skill for use. Further, to measure extension muscle strength of the whole lower extremities, a dynamometer which is expensive and has a large space is required.
The larger the lower extremity muscle strength to be checked when a subject sits in a chair having a predetermined height and then rises, the subject may load more body weight to legs to be checked, but required muscle contraction is continuously changed to maintain load body weight to leg while the subject sits down and then stands up, and therefore the muscle strength cannot be measured by means of scales at both lower extremities.
In this case, a load extent of a body weight may be measured based on a ground reaction force.
When the subject sits in a chair and then rises, the largest muscle contraction of the lower extremities is occurring at the moment or near the moment that a body is separated from the chair. Therefore, the muscle strength may be measured based on the ground reaction force generated by the lower extremities to be measured at the moment that the body is separated from the chair.
Therefore, various researches into a rehabilitation device for evaluate muscle strength of muscle weakness paralysis symptoms and patients with paralysis symptoms have been conducted.
Korean Patent Laid-Open No. 10-2009-0117084 (filed on Nov. 30, 2009) discloses a user-customized gait rehabilitation device.